This patch uses scalar_int_modes for:
/* If I2 is setting a pseudo to a constant and I3 is setting some
sub-part of it to another constant, merge them by making a new
constant. */
This was already implicit, but the danger with checking only
CONST_SCALAR_INT_P is that it can include CC values too.
2017-07-13 Richard Sandiford <richard.sandif...@linaro.org>
Alan Hayward <alan.hayw...@arm.com>
David Sherwood <david.sherw...@arm.com>
gcc/
* combine.c (try_combine): Use is_a <scalar_int_mode> when
trying to combine a full-register integer set with a subreg
integer set.
Index: gcc/combine.c
===================================================================
--- gcc/combine.c 2017-07-13 09:18:45.761227536 +0100
+++ gcc/combine.c 2017-07-13 09:18:49.526933168 +0100
@@ -2645,6 +2645,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2,
rtx other_pat = 0;
rtx new_other_notes;
int i;
+ scalar_int_mode dest_mode, temp_mode;
/* Immediately return if any of I0,I1,I2 are the same insn (I3 can
never be). */
@@ -2847,33 +2848,40 @@ try_combine (rtx_insn *i3, rtx_insn *i2,
constant. */
if (i1 == 0
&& (temp_expr = single_set (i2)) != 0
+ && is_a <scalar_int_mode> (GET_MODE (SET_DEST (temp_expr)), &temp_mode)
&& CONST_SCALAR_INT_P (SET_SRC (temp_expr))
&& GET_CODE (PATTERN (i3)) == SET
&& CONST_SCALAR_INT_P (SET_SRC (PATTERN (i3)))
&& reg_subword_p (SET_DEST (PATTERN (i3)), SET_DEST (temp_expr)))
{
rtx dest = SET_DEST (PATTERN (i3));
+ rtx temp_dest = SET_DEST (temp_expr);
int offset = -1;
int width = 0;
-
+
if (GET_CODE (dest) == ZERO_EXTRACT)
{
if (CONST_INT_P (XEXP (dest, 1))
- && CONST_INT_P (XEXP (dest, 2)))
+ && CONST_INT_P (XEXP (dest, 2))
+ && is_a <scalar_int_mode> (GET_MODE (XEXP (dest, 0)),
+ &dest_mode))
{
width = INTVAL (XEXP (dest, 1));
offset = INTVAL (XEXP (dest, 2));
dest = XEXP (dest, 0);
if (BITS_BIG_ENDIAN)
- offset = GET_MODE_PRECISION (GET_MODE (dest)) - width - offset;
+ offset = GET_MODE_PRECISION (dest_mode) - width - offset;
}
}
else
{
if (GET_CODE (dest) == STRICT_LOW_PART)
dest = XEXP (dest, 0);
- width = GET_MODE_PRECISION (GET_MODE (dest));
- offset = 0;
+ if (is_a <scalar_int_mode> (GET_MODE (dest), &dest_mode))
+ {
+ width = GET_MODE_PRECISION (dest_mode);
+ offset = 0;
+ }
}
if (offset >= 0)
@@ -2882,9 +2890,9 @@ try_combine (rtx_insn *i3, rtx_insn *i2,
if (subreg_lowpart_p (dest))
;
/* Handle the case where inner is twice the size of outer. */
- else if (GET_MODE_PRECISION (GET_MODE (SET_DEST (temp_expr)))
- == 2 * GET_MODE_PRECISION (GET_MODE (dest)))
- offset += GET_MODE_PRECISION (GET_MODE (dest));
+ else if (GET_MODE_PRECISION (temp_mode)
+ == 2 * GET_MODE_PRECISION (dest_mode))
+ offset += GET_MODE_PRECISION (dest_mode);
/* Otherwise give up for now. */
else
offset = -1;
@@ -2895,23 +2903,22 @@ try_combine (rtx_insn *i3, rtx_insn *i2,
rtx inner = SET_SRC (PATTERN (i3));
rtx outer = SET_SRC (temp_expr);
- wide_int o
- = wi::insert (rtx_mode_t (outer, GET_MODE (SET_DEST (temp_expr))),
- rtx_mode_t (inner, GET_MODE (dest)),
- offset, width);
+ wide_int o = wi::insert (rtx_mode_t (outer, temp_mode),
+ rtx_mode_t (inner, dest_mode),
+ offset, width);
combine_merges++;
subst_insn = i3;
subst_low_luid = DF_INSN_LUID (i2);
added_sets_2 = added_sets_1 = added_sets_0 = 0;
- i2dest = SET_DEST (temp_expr);
+ i2dest = temp_dest;
i2dest_killed = dead_or_set_p (i2, i2dest);
/* Replace the source in I2 with the new constant and make the
resulting insn the new pattern for I3. Then skip to where we
validate the pattern. Everything was set up above. */
SUBST (SET_SRC (temp_expr),
- immed_wide_int_const (o, GET_MODE (SET_DEST (temp_expr))));
+ immed_wide_int_const (o, temp_mode));
newpat = PATTERN (i2);
